From: Alexandru Ardelean <ardeleanalex@gmail.com>
To: Alexandru Ardelean <alexandru.ardelean@analog.com>
Cc: linux-iio <linux-iio@vger.kernel.org>,
linux-stm32@st-md-mailman.stormreply.com,
LKML <linux-kernel@vger.kernel.org>,
linux-arm-kernel@lists.infradead.org,
Jonathan Cameron <jic23@kernel.org>,
alexandre.torgue@st.com, Fabrice Gasnier <fabrice.gasnier@st.com>,
Sergiu Cuciurean <sergiu.cuciurean@analog.com>
Subject: Re: [PATCH v2] iio: stm32-dac: Replace indio_dev->mlock with own device lock
Date: Thu, 27 Aug 2020 11:55:37 +0300 [thread overview]
Message-ID: <CA+U=DsrMDSTQKEc2_3+W8u4bLraAowVB3nB4huKY--v8gnds2Q@mail.gmail.com> (raw)
In-Reply-To: <20200826120042.200364-1-alexandru.ardelean@analog.com>
On Wed, Aug 26, 2020 at 3:03 PM Alexandru Ardelean
<alexandru.ardelean@analog.com> wrote:
>
> From: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
>
> As part of the general cleanup of indio_dev->mlock, this change replaces
> it with a local lock. The lock protects against potential races when
> reading the CR reg and then updating, so that the state of pm_runtime
> is consistent between the two operations.
>
> Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
> ---
Forgot the changelog here.
Apologies.
Changelog v1 -> v2:
* removed whitespace change for 'common' field
* updated comment about the lock usage
> drivers/iio/dac/stm32-dac.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iio/dac/stm32-dac.c b/drivers/iio/dac/stm32-dac.c
> index 092c796fa3d9..7a8aed476850 100644
> --- a/drivers/iio/dac/stm32-dac.c
> +++ b/drivers/iio/dac/stm32-dac.c
> @@ -26,9 +26,11 @@
> /**
> * struct stm32_dac - private data of DAC driver
> * @common: reference to DAC common data
> + * @lock: lock to protect the data buffer during regmap ops
> */
> struct stm32_dac {
> struct stm32_dac_common *common;
> + struct mutex lock;
> };
>
> static int stm32_dac_is_enabled(struct iio_dev *indio_dev, int channel)
> @@ -58,10 +60,10 @@ static int stm32_dac_set_enable_state(struct iio_dev *indio_dev, int ch,
> int ret;
>
> /* already enabled / disabled ? */
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&dac->lock);
> ret = stm32_dac_is_enabled(indio_dev, ch);
> if (ret < 0 || enable == !!ret) {
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&dac->lock);
> return ret < 0 ? ret : 0;
> }
>
> @@ -69,13 +71,13 @@ static int stm32_dac_set_enable_state(struct iio_dev *indio_dev, int ch,
> ret = pm_runtime_get_sync(dev);
> if (ret < 0) {
> pm_runtime_put_noidle(dev);
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&dac->lock);
> return ret;
> }
> }
>
> ret = regmap_update_bits(dac->common->regmap, STM32_DAC_CR, msk, en);
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&dac->lock);
> if (ret < 0) {
> dev_err(&indio_dev->dev, "%s failed\n", en ?
> "Enable" : "Disable");
> @@ -327,6 +329,8 @@ static int stm32_dac_probe(struct platform_device *pdev)
> indio_dev->info = &stm32_dac_iio_info;
> indio_dev->modes = INDIO_DIRECT_MODE;
>
> + mutex_init(&dac->lock);
> +
> ret = stm32_dac_chan_of_init(indio_dev);
> if (ret < 0)
> return ret;
> --
> 2.25.1
>
next prev parent reply other threads:[~2020-08-27 8:55 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-26 6:38 [PATCH] iio: stm32-dac: Replace indio_dev->mlock with own device lock Alexandru Ardelean
2020-08-26 8:57 ` Fabrice Gasnier
2020-08-26 10:01 ` Alexandru Ardelean
2020-08-26 12:00 ` [PATCH v2] " Alexandru Ardelean
2020-08-27 8:55 ` Alexandru Ardelean [this message]
2020-08-27 9:03 ` Fabrice Gasnier
2020-08-27 10:00 ` Alexandru Ardelean
2020-08-29 15:46 ` Jonathan Cameron
2020-09-02 6:12 ` Alexandru Ardelean
2020-09-16 9:23 ` Alexandru Ardelean
2020-09-16 10:18 ` Fabrice Gasnier
2020-09-16 17:52 ` Jonathan Cameron
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